1. Field Of The Technology
The technology presented herein relates to a photoelectric conversion device and a method of producing the same, and more particularly to a photoelectric conversion device such as a solar cell, a sensor or the like produced by a plasma CVD method or the like, and a method of producing the same.
2. Description of the Related Art
In recent years, thin-film photoelectric conversion devices which are formed from gases as a raw material by a plasma CVD method receive attention. Examples of such thin-film photoelectric conversion devices include silicon base thin-film photoelectric conversion devices including a silicon base thin-film, thin-film photoelectric conversion devices including CIS (CuInSe2) compounds or CIGS (Cu (In, Ga) Se2) compounds, and the like, and development of these devices are accelerated and their quantity of production is increasingly enlarged. A major feature of these photoelectric conversion devices lies in a fact that these devices have potential that cost reduction and higher performance of the photoelectric conversion device can be simultaneously achieved by stacking a semiconductor layer or a metal electrode film on a low-cost substrate with a large area with a formation apparatus such as a plasma CVD apparatus or a sputtering apparatus, and then separating/connecting photoelectric conversion devices prepared on the same substrate by laser patterning.
In the case of producing such photoelectric conversion devices, it is common to use a plasma CVD apparatus having a plurality of film forming chambers in which semiconductor layers with different conductive types are formed in different film forming chambers. As such an apparatus, an in-line method or multi-chamber system is adopted. However, it is common that these apparatuses are large in size and complicated. Therefore, increasing production cost of photoelectric conversion devices due to the increased cost of a production apparatus is a barrier to large-scale widespread use of photoelectric conversion devices.
In view of these problems, Japanese Unexamined Patent Publication No. 2000-252495 discloses a single chamber system in which a p-type semiconductor layer, an i-type crystalline silicon base photoelectric conversion layer and an n-type semiconductor layer are formed in order in succession in the same plasma CVD forming chamber. In this method, the number of the film forming chambers can be reduced and equipment can be simplified in comparison with the in-line method and the multi-chamber system. Further, there is an advantage that delivery between the film forming chambers becomes unnecessary and a production time of the photoelectric conversion device is also reduced.
A method (a single chamber system) disclosed in Japanese Unexamined Patent Publication No. 2000-252495 is a method of forming semiconductor layers of a tin film photoelectric conversion device, in which a photoelectric conversion device having a p-type semiconductor layer, an i-type semiconductor layer and an n-type semiconductor layer is formed in the same film forming chamber by a plasma CVD method. In the formation method, there is a problem that since determinant impurity atoms of a conductive type with which the p-type semiconductor layer and n-type semiconductor layer are doped, are introduced into other different kinds of semiconductor layers, a photoelectric conversion device having good photoelectric conversion characteristics is hard to obtain. In particular, when determinant impurity atoms of a conductive type of a p-type or an n-type mix in the i-type semiconductor layer, a carrier concentration increases, and therefore an internal electric field near a p-i interface or a i-n interface in the i-type semiconductor layer is weakened. This is a large cause of deterioration of the photoelectric conversion characteristics.